Many electronic devices include illuminated surfaces. For example, some keyboards illuminate keys so that the keyboard can be used in low or no lighting conditions. Additionally, keys may be illuminated simply to aid users in understanding the functions associated with various keys, such as by illuminating a legend on a surface of a key.
This surface lighting is generally implemented by mounting a light emitting diode (LED) on a printed circuit board (and/or flexible circuits and/or wires connected thereto) under a key. Due to this placement, light guide panels and/or other structures are often used in order to distribute light from the LED evenly as well as prevent or reduce “hot spots” (areas of comparative brightness corresponding to the actual location of an LED).
Such light guide panels or other structures occupy space in a key stack, making key stack dimensions larger than they otherwise would be and/or limiting the components that could otherwise be included. Further, even with such light guide panels or other structures, greater amounts of power may be provided to an LED than would otherwise be used with the LED alone in order to obtain a desired illumination level due to the position of the LED or other structures, distance from the key cap, the diffusion of light, and so on.